JPH086025B2 - Stabilization of polyols by liquid anti-scorch composition - Google Patents

Abstract

The invention relates to the use of certain styrenated diphenylamine and hindered phenol compositions for the stabilization of polyether polyols.

Description

BACKGROUND OF THE INVENTION Field of the Invention The present invention relates to the stabilization of polyoxyalkylene polyether polyols and the use of the stabilized polyols in the production of polyurethane foams. The invention is particularly
It relates to the stabilization of polyols with certain liquid stabilizer compositions and to the inhibition of coloration or scorch of flexible and semi-flexible polyurethane foams made from the stabilized polyols.

BACKGROUND AND RELATED ART Conventional stabilization methods for polyalkylene polyether polyols with antioxidants or stabilizers and the use of the stabilized polyols for controlling scorch in the production of polyurethane foams are well known.

U.S. Pat.Nos. 3,567,664 and 3,637,865 describe a mixture of 2,6-di-tert-butyl-4-methylphenol [butylated hydroxytoluene (BHT)] and p, p'-dialkyldiphenylamine. A stabilized polyurethane foam is disclosed. U.S. Pat. No. 4,010,211 teaches the addition of phenothiazine to a BHT / p, p'-dialkyldiphenylamine mixture. U.S. Pat.No. 4,794,126 describes diaryl arylenediamines, which are reaction products of diaryl amines with alkyl ketones, and sterically hindered phenols, specifically
Disclosed are flame retardant polyurethane foams stabilized by combination with 3,6'-di-tert-butyl-4-tert-butylphenol. The above-mentioned conventional stabilizers are solids and are generally dissolved in the polyol medium by heating. A large amount of all polyol material is subjected to a filtration step to remove any undissolved solid stabilizer, after which the polyol precursor can be cured to the final foam product.

Statton is J. CELLULAR PLASTICS , No. 34
Page 6 (1984) “Evaluation of sterically hindered phenols to minimize foam discoloration using the microwave scorch test method (Hindered Phenols for Min
imization of Foam Discoloration Using the Microwav
e Scorch Test) ”is a solid antioxidant p,
Four phenols were studied in combination with p'-dioctyldiphenylamine alone and in the presence of phenothiazine. Although the system containing BHT sterically hindered phenols was a fairly effective stabilizing package for polyols, 2,6-di-tert-butyl-4-
The system consisting of sec-butylphenol and p, p'-dioctyldiphenylamine did not give satisfactory scorch resistance. In the Statton system described, the amine appeared to be more effective than the phenolic stabilizer in reducing scorch. This combination does not appear to give good scorch resistance to the polyols used, even at maximum concentration.

U.S. Pat.No. 4,933,374 discloses a stabilizing amount of 2,6
Oxidation with a synergistic mixture of di-tert-butyl-4-tert-butylphenol and the reaction product of diisobutylene, styrene and diphenylamine with a weight ratio of diisobutylene to styrene of about 2: 1 to 5: 1. Disclosed are polyoxyalkylene polyether polyol compositions protected against aging.

Therefore, it would be advantageous to have a liquid polyol stabilizer system that is soluble in the polyol medium at ambient temperature. In that way, two steps of the conventional method could be omitted: the step of dissolving the stabilizer in the polyol medium by heating and the step of removing the undissolved solid stabilizer by filtration. Unexpectedly, an additional benefit of liquid stabilizer compositions is their ability to be added to polyols by metering or delivery, which provides additional convenience and safety.

SUMMARY OF THE INVENTION The stabilizing system of the present invention is a synergistic blend of liquids. It has been discovered that certain styrenated diphenylamines provide excellent scorch resistance when they are combined with certain sterically hindered phenols.

Another aspect of the present invention is a method of stabilizing polyalkylene polyether polyols against oxidative degradation and the use of such stabilized polyols with polyisocyanates to produce polyurethane foams that are stabilized with respect to scorch. Regarding things.

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to the use of compositions of styrenated diphenylamine and sterically hindered phenols for stabilizing polyols.

Unexpectedly, the styrenated diphenylamine /
The sterically hindered phenolic composition produces a synergistic antioxidant effect on the polyol when combined in certain proportions.

Styrenated amines can be prepared from diphenylamines that can be easily alkylated with vinyl aromatics, as taught, for example, in US Pat. Nos. 3,505,225 and 3,649,690. Both of the above US patents are incorporated herein by reference.

The styrenated diphenylamine used is ortho-,
It has varying amounts of each isomer combination selected from the group consisting of para-, ortho- / ortho-, ortho- / para-, para- / para- and tristyrenated diphenylamine. These isomers have the formula I: Can be represented by Wherein R ¹ , R ² , R ³ and R ⁴ may be the same or different, and And hydrogen. However, R ¹ , R ² , R ³
And R ⁴ cannot be all hydrogen. Groups R ¹ , R ² ,
The position and number of R ³ and R ^{4 on} the diphenylamine are all important, as will be apparent from the examples below.

Of the blend of diphenylamine derivative isomers having Formula I above, the para / para isomer of the formula wherein R ² and R ³ are hydrogen may comprise from 31 wt% to 43 wt% of the diphenylamine isomer blend. is important.

The phenolic component is of formula II It has the structure of. Wherein R ⁵ , R ⁶ and R ⁷ may be the same or different and are selected from the group consisting of C ₁ -C ₈ alkyl, phenyl and phenyl (C ₁ -C ₆ ) alkyl.
There are two types of phenols of formula II, commercially available as liquids and as low melting solids. R ⁵ is CH
_When R ⁶ and R ⁷ are tertiary butyl groups, the compound of formula II is what is commonly known as butylated hydroxytoluene (BHT) and is available from Uniroyal Chemical Company Inc. Marketed by Naugard BHT. Another phenol is marketed under the trademark VANOX 132 [RT Vanderbilt Compan
y)], R ⁵ is sec-butyl and R ⁶ and R ⁷ are both tert-butyl.

In the table below, the isomer mixture of styrenated diphenylamine and 2,6-di-tert-butyl-4-tert-butylphenol (Vanox 132) were combined in various ratios. Performance tests as stabilizers for polyols were also performed for each combination. The quantities listed in Table I are in parts per million by weight. The scorch resistance of the resulting polyurethane foam was measured by the microwave scorch test described below.

Examples 1-7 A premix of 10.0 grams of water, 0.40 grams of A-1 * and 0.2 grams of L-5810 **, with minimal initial stabilization (BHT · 100ppm), is shown in Table I below. 200 grams of a 3000 polyol average molecular weight polyether polyol also containing the indicated stabilizer package was added. The mixture was stirred for 5 seconds in a high speed Lightning Mixer. Then 0.40 grams of T-10 catalyst *** was added and the resulting mixture was mixed in the same lightening mixer 5 times.
Stir for 2 seconds. Finally, 126.0 grams of TDI-80 *****
And the mixture in the same lightning mixer 7
Stir for 2 seconds, then 25 x 25 x 12.5 cm (10 "x 10" x
5 ″) cardboard box. The foam was allowed to fully expand at room temperature and then left for another 5 minutes. After removing the sides of the box, the material was placed in a microwave oven at 50% power for 5 minutes 30 minutes. The foams were then immediately cured in an air oven for 3 minutes at 125 ° C., followed by slicing the buns in half and observing the internal discoloration.

Performance / scorch rating is based on the following scale: 1 = no discoloration (white) to trace yellow 2 = slightly yellow 3 = light yellow 4 = dark yellow / slightly brown 5 = light brown 5 + = dark brown / burnt Notes to the Table The isomer composition of Sample 1 is shown in the first row of Table II.

 The isomer composition of Sample 4 is shown in Table II, line 4.

* A-1 is Union Carbide
Is a tertiary amine catalyst sold by.

** L-5810 is a Silicone surfactant sold by Union Carbide.

*** T-10 is a tin catalyst, specifically stannous octoate in dioctyl phthalate.

*** TDI-80 is a toluene diisocyanate (2,6: 80% -2,4: 20%) sold by Mobay.

The performance test results given in Table I show that compositions 4 and 5
Have the highest performance grade. Further from the table above, the optimum ratio of phenol: amine combination is 40: 6.
It can be seen that the range is 0 to 60:40.

Examples 8-15 Further studies with controlled phenol: amine ratios, and by observing the scorch stability of the stabilized polyols, the amount of each regioisomer of the styrenated diphenylamine and various phenols were investigated. The ratio with the quantity was compared.

The polyol used in these tests was the commercially available polyol Voranol 3137 [Dow Corporati
on)] or Niax 16-52 (trademark of Union Carbide). The average molecular weight of these materials is about 3000.

The samples shown in Table II were analyzed by gas chromatography using a Varian 3400 chromatograph. 1 meter packed column and flame ionization detector (f1
ame ionization detector) was also used.

The amounts of each styrenated diphenylamine isomer found by the above gas chromatographic method are shown in Table II. These amounts are given by the gc area percent of each amine component.

The sterically hindered phenol: diphenylamine ratio of each of Compositions 8-11 was 60:40 and the amount of total stabilizer package added to the polyol was 0.45% (by weight). In Compositions 8-11, the sterically hindered phenol used was Vanox 132.

The sterically hindered phenol: diphenylamine ratio of each of Compositions 12-15 was 50:50 and the amount of total stabilizer package added to the polyol was 0.5% (by weight). In Compositions 12-15, the sterically hindered phenol used was
It was BHT.

In all compositions, the polyol used is valanol
It was 3137 or Niax 16-52. Choosing any one of the above polyols did not make a difference in performance results.

A description of the subject matter of each column of Table II is as follows: Referring to the general structure of Formula I of styrenated diphenylamine, o represents styryl substitution at the R ² position only, and R ¹ = R ³ = R ⁴
= H; p represents styryl substitution only at the R ¹ position, R ² = R ³ = R ⁴
= H; o / o represents styryl substitution at the positions of R ² and R ³ ,
¹ = R ⁴ = H; p / p represents styryl substitution at the R ¹ and R ⁴ positions, R /
² = R ³ = H; and tri indicates that 3 styryl substituents are present at the R ² , R ³ and R ⁴ positions and R ¹ = H.

The above data and performance / scorch results show an unexpected and significant trend for the styrenated diphenylamine component of the synergistic stabilizer system of the present invention. It is well known in the industry that performance / scorch values greater than 2 are unacceptable to polyol manufacturers. From the above data, it is clear that only samples 8, 14 and 15 have acceptable performance / scorch values.

It is also clear from the above data that the isomer content of the preferred compounds has a para / para isomer ratio of 25% to 55% of the total analytical value. The preferred isomer ratio is 30% to 50%, more preferably 31% to 43%.

The compositions of the present invention can be incorporated into the polyol precursor in any amount effective to produce the desired stability. Amounts of about 0.3 to 1.0 percent are typically sufficient. The preferred range is about 0.4% to 0.6% by weight of the total polyol composition. Due to the liquid state of the stabilizer compositions of the present invention, these stabilizer compositions can be incorporated into the polyol by stirring at ambient temperature.

Among the polyol components that can be stabilized by the stabilizer composition of the present invention are polyoxyalkylene polyether polyols having from about 2 to about 10 hydroxy groups per molecule. About 200 to 10, especially suitable polyols
Some have a molecular weight of 000 or higher. Polyols derived from diols and triols are preferred,
The molecular weight range is then about 100 for diols to about 6000 for triols.

These polyether polyols have 2 or 3 or more ether groups in the molecule. These polyols are derived, inter alia, from ethylene chioside, propylene oxide, epichlorohydrin, styrene oxide, diethylene glycol, triethylene glycol, trimethylolpropane, glycerine, hexanetriol, butanetriol and the like. .
Suitable polyether polyols for the production of flexible polyurethane foams and their method of manufacture are PLASTIC FOAMS ,
Frisch (Part 1), pp. 118-125 (1972)
h) and Saunders (editor).

In the manufacture of flexible polyurethane foams, the stabilized polyol composition comprises a polyisocyanate containing 2 or more -N = C = O groups per molecule, a catalyst, a surfactant, water and optional components. As a foaming auxiliary. Commercially available polyisocyanates include, among others, (2,4- and / or 2,6) toluene diisocyanate, 4,4'-diphenylmethane diisocyanate, polyisocyanates from aniline-formaldehyde oligomers, and aliphatic isocyanates such as methylcyclohexane diisocyanate. And the like.

Most stabilizer compositions tend to discolor when left to stand. To prolong the shelf life of the compositions of the present invention, a trihydrocarbyl phosphite is used, in which the hydrocarbyl groups can be independently selected from phenyl and alkyl groups.
It is advantageous to add 0.5% to 10.00%. 5 to 13
Alkyl derivatives having one and more carbon atoms are preferred. The compounds tridecyl phosphite and phenyldiisodecyl phosphite are particularly preferred. These compounds are well known as peroxide scavengers, and their use as color stabilizers is also well known to those skilled in the art.

Due to increased safety considerations, flexible and semi-flexible polyurethanes may contain flame retardants. Flame retardants are known compounds containing phosphorus, antimony, boron, bismuth and halogen atoms or combinations thereof. Polyurethane is another additive,
For example, it may contain a filler, a plasticizer, a deodorant, an ultraviolet stabilizer, a heat stabilizer and the like.

The data provided herein are for illustration purposes and do not limit the scope of the invention in any way. Other modifications will be apparent to those skilled in the art and such modifications are also within the scope of the invention.

 ─────────────────────────────────────────────────── ——————————————————————————————————————————————————————————— Inventor Barry, Lawrence, Bee. 75 Ponderosa Lane, Newington, Connecticut, USA 75 (72) Inventor Richardson, Mark, Sea. United States 06410 Hall Drive, Cheshire, Connecticut 70. (56) References US Patent 4933374 (US, A) UK Patent 1494538 (GB, A)

Claims (8)

[Claims] 1. A) A blend of diphenylamine isomers having the formula I below, wherein the para / para isomer of the formula wherein R ² and R ³ are hydrogen is 31% to 43% by weight of the diphenylamine isomer blend. % Of the amine comprising the blend: (In the formula, R ¹ , R ² , R ³ and R ⁴ may be the same or different, and iii) and hydrogen; however, R ¹ , R ² and R ³ cannot all be hydrogen. ); And b) formula (In the formula, R ⁵ , R ⁶ and R ⁷ may be the same or different,
The C ₁ -C ₈ alkyl, phenyl and phenyl (C ₁ ~
C ₆ ) alkyl selected from the group consisting of. Liquid amine / phenolic stabilizers for polyols comprising phenols with). 2. A weight ratio of amine to phenol of 60:40 to 40:
A liquid stabilizer for polyols according to claim 1 which is 60. 3. A method according to claim 1, further comprising 0.5% to 10.0% by weight of trihydrocarbyl phosphite, wherein the hydrocarbyl groups can be independently selected from phenyl and alkyl groups. A liquid stabilizer for the polyol as described in 1. 4. A liquid stabilizer for polyols according to claim 3, wherein the trihydrocarbyl phosphite is tridecyl phosphite. 5. A blend of (1) a polyether polyol having 2 to 10 hydroxy groups; and (2) a) a blend of diphenylamine isomers having formula I below, wherein R ² and R ³ are: The para / para isomer that is hydrogen is 31 of the diphenylamine isomer blend.
Amine consisting of the blend making up from wt% to 43 wt%: (In the formula, R ¹ , R ² , R ³ and R ⁴ may be the same or different, and iii) and hydrogen; where R ¹ , R ² , R ³ and R ⁴ cannot all be hydrogen. ); And b) formula (In the formula, R ⁵ , R ⁶ and R ⁷ may be the same or different,
The C ₁ -C ₈ alkyl, phenyl and phenyl (C ₁ ~
C ₆ ) alkyl selected from the group consisting of. A stabilized polyether polyol composition comprising a liquid two-component amine / phenolic stabilizer for a polyol comprising: 6. Stabilizer is from 0.3% by weight based on the total composition.
Stabilized polyether polyol composition according to claim 5, wherein 1.0% by weight is present. 7. A weight ratio of amine to phenol of 60:40 to 40:
The stabilized polyether polyol composition of claim 5 which is 60. 8. A further content of 0.5 to 10.0% by weight, relative to the stabilizer, of trihydrocarbyl phosphite, wherein the hydrocarbyl groups can be independently selected from phenyl and alkyl groups. The stabilized polyether polyol composition of claim 5.